Handheld laser system

Abstract

A handheld laser system. In certain examples the handheld laser system includes a laser source emitting laser light at a wavelength for performing a material processing operation on a workpiece material with a laser beam of the emitted laser light, a plasma sensor configured to detect plasma emitted from tire workpiece material daring a material processing operation, and a controller coupled to the plasma sensor and configured to: compare an optical intensity value obtained by the plasma sensor to a threshold value at a time when a predetermined time period has elapsed after the material processing operation has commenced, and produce a control command based on the comparison.

Description

HANDHELD LASER SYSTEM REFERENCE TO PRIOR APPLICATIONS “This application claims the benefit of U.S. Provisional Patent Application No. £3 / 069,816 filed on August 25, 2020, and to U.S. Provisional Patent Application No. 63 / 089,113 fled on Ocwber 8, 2020, cach of which is herein incorporated by reference in its entirety. BACKGROUND Technical Field The technical field relates genenlly © a handheld laser device that can be used for material processing operations, and more specifically tw a handheld laser device configured with a plasma sensor. Background Discussion The use of lasers in material processing applications has mereased over the last four decades and is becoming increasingly important in modern manafretering processes. Lasers are used in a variety of applications, including welding, cutting, diilling, surface hardening, and additive manufhoturing. Fiber lasers tn particular offer several! advantages over other laser technologies, such as excimer or COz systems. For example, fiber laser technology provides lower maintenance costs by eliminating downtime, reducing the spares inventory, decreasing the cost of processing gas and electricity, and in many stances lowering labor costs associated with keeping older types of lasers operational. Besides a lower cost of ownership, fiber laser technology also offers high wall plug efficiencies, long diode Hietimes, minimal mabnenance, and versatility since the same wut can often caf, weld, or dull Because of thew physical size, the fiber laser can also be ensily transported. Tn addition, they offer low beam divergence and do not require warm-up since there is no spot stze change with power, and possess a large dynamic range. Handheld laser devices have up antl now have been used in low power applications, scioding medical devices and diagnostic instrumentation. While ugher power lasers (e.g, at least | KW) have been conventionally used for industrial cutting snd welding in the industrial community, these systems have typically been too expansive for many smailer machine shops or other smaller-scale snd users. However, over ime the average power of laser diodes has increased significantly while their average price per walt has decressed exponentially, In addition, technological advances have beso made in higher power laser systems. These factors make it more feasible wo implement higher power lasers info smaller material processing systems, such as handheld laser devices. Such systems would not only be desirable for smaller industrial shops, but these devices would be especially useful in applications where larger systems are impractical or impossible to use. For example, these portable, i.e, easy to move devices are useful in small work spaces, and can be used in applications where there are regolar geometres or shapes. Hindering at least one of these objectives is the conventional use of large water-based or hguid refrigerant-based chillers asad to cool the lasers. The large siee associated with these systems makes it not enly more difficult to maneuver the system, but may make it impossible to we in small work spaces. With increasing laser power, 80 are hazards associated with laser ght. Since laser Hght used in machining operations such as welding and cutting {o.g., infrared} is invisible to the Fuman eye, the hazards may not be readily apparent fo a user. {f there is a problem associated with the laser energy emanating from the handheld device, this may not be readily apparent to the ase. For example, if the laser energy is reflected off the workpiece material instead of being absorbed, the reflected energy can potentially harm the user, as they can unintentionally expose themselves to prolongad invisible mdiation since they believe that the Taser is not functioning. SUMMARY Aspects and non-limiting examples are directed to methods and systems for material processing operations using a handheld laser device. Ir secordance with one aspect of the disclosure, a handheld laser system fs provided that ineludes & laser source configured to generate laser radiation at a wavelength for performing a material processing operation on & workpiece material with a laser beam of the generated laser radiation, a plasma sensor configured to detect plasma emitted from the workpiece material daring a material processing opesation, and a controller coupled fo the plasma sensor and configured wr compare an optical intensity vatoe obained by the plasma sensor to a teshold value ata time whens a predetermined tine period has elapsed after the material processing operation has conmenved, sud produce a control command based on the comparison. Tn some aspects, the control conumand turns off power to the laser sources when the optical intensity value is lower than the threshold value, and maintains power to the laser source when the optical intensity value is at or greater than the threshold value. In further aspects, the predetermined time period iy at least 100 nucraseconds (us). In some aspects, the handheld laser system further inchudes at least one optical filter configured fo block Hight at the wavelength of the emitted laser Hight from reaching the plasma sensor. fn some aspeety, the handheld laser system further includes an abr-cooling system coupled to the laser source for dissipating heat. Tn further aspests, the handheld laser system fiwther includes a laser module that houses the laser sowree, the afr-cooling system, and the controller. In further aspects, the laser module is configured to be mounted 10 a movable can. Tn some aspects, the handheld laser system fiether fneludes a housing configured as 8 handheld apparatus having an outlet for the laser beam. In further aspeots, the handheld laser system further Includes at least one movable mirror positioned within the housing, the a least one movable mirror configured to wobble the laser beam, In further aspects, the handheld apparatus is of one-piece construction. In further aspects, the handheld apparatus is configured with 2 wodalar attacheent system for a nozsle, In further aspects, the handheld apparatus is configured to be gas-conled. To further aspeots, the handheld apparatos fs configored to weigh less than about § Kilogram (kg). In further sapects, the plasma sensor is positioned within an interior of the handheld apparatus. In further aspects, the handheld laser system further includes an optical Sher coupling the handheld apparatus to the laser source. fn some aspects, the handheld apparatus further includes & trigger coupled fo at least one of the controller and 8 sows of shield gas that controls sotivation of the shield gas. In further aspects, the trigger is a first trigger and the handheld apparatus further comprises a second trigger coupled to at least one of the controller and the laser source that controls activation of the laser source. In further aspenty, the first and second triggers are configured in a two-stage arrangement such that the second trigger will not activate the laser scarce unless the frst rigger is activated. In some aspects, the laser bean has a power of at least 1 kW, fr some aspects, the laser beam kas a power of about 1.5 kW. Ti some aspects, the laser beam has a power within a range of 360 W to 3 kW inclusive. In some aspeets, the laser source is configured fo: generate laser radiation ina continuous wave (CW) mode that has an oaiput power, and generate laser radiation in a high peak power (HPP) mode characterized by having s maximum peak power that is Jess than twice the onfput power of the TW mode, & maxima duty eyele of about 20%, and a maxinnen pulss-repetition frequency of about 1800 Ha In seane aspects, the wavelength fs infrared (IR) Hght and the at Isast one optical filter is configured ac an IR suppression Slter, In sceordance with another aspect of the disclosare a method is provided that includes directing a laser beam from a laser source onto a workpiece material, activating 2 plasma sensor configured to detect plasma emitted from the workpiece material during a material processing operation, comparing an optical intensity value obtained by the plasma sensor toa threshold value at a the when a predetenmined time period has lapsed after the material processing operation bas commenced, and producing a control command based on the COMPATISon. In sowne aspects, the control command powers off the laser source when the optics! intensity value is lower than the threshold value and maintains power to the lager source when the optical intensity value is at or greater than the threshold valve, In farther aspeets, the method includes positioning at least one optical filter configured (0 block light at a wavelength of the laser source such that light at the wavelength of the laser source does not reach the plasma sensor. In further aspects, the method fnchudes providing a housing configured as a handheld apparates having an outst for the laser beam. Tn further aspects, the method includes providing an optical fiber that couples the handheld apparatus to the laser sowree, In some aspects, the method includes wobbling the laser beam. In accordance with another aspect of the disclosure, a handheld laser system is provided that includes a laser source configured to generate laser radiation at a wavelength for performing & material processing operation on a workpiece material with a faser beam of the generated laser radiation, and a housing configured as a handheld apparatus having an outlet for the laser beam, the handheld apparatus configured to be gas-cooled. In further aspects, the handheld laser system includes an optical fiber coupling the handheld apparatus to the laser source. in some aspects, the handheld apparatus {8 of one-piece constuction. In some aspeets, handheld apparatus is configured with a modular attachment system {or a nozzle. Tn some aspeots, the handheld laser system further includes an air-cooling system coupled to the laser source for dissipating heat. In some aspects, the handheld laser system further includes a laser module that houses the laser source, the ais-cooling system, and the controller. Io further aspects, the laser module is configured to be mounted © a movable cart, In some aspects, the laser beam has 4 power of at least | kW. Still other aspects, embodiments, and advantages of these example aspects and embodiments, are discussed in detedl below, Moraover, Us to be understood that both the foregoing formation and the following detailed description ave merely Husttative examples of various aspeats and embodiments, and are intended to provide an overview or framework for understanding the nature and character of the claimed aspects and embodiments, Embodiments disclosed herein may be combined with other embodiments, and references to “an embodiment,” “an example.” “some embodiments,” “some examples,” “an alternate embodiment,” “various embodiments,” “one embodiment,” “at least one embodiment,” “this and other embodiments,” “eertain embodiments,” or the Hke are not necessarily mutually exclusive and are intended to fndicate that a particular feature, stricture, or characteristic described may be included in at least one vmbodiment. The appearances of such terms hersin are not necessarily all referring fo the same embodiment, Various aspeots of one or more embodiments are discussed below with reference to the accompanying figures, which are not intended to be draws to scale, The figures are included to provide an ilostration and a further understanding of the various aspects and embodiments, and are incorporated in and constitute a part of this specification, but ave not intended as a defirution of the fumits of any particular embodiment. The drawings, together with the remainder of the specification, serve to explain principles and operations of the described and claimed aspects and embodiments. To the figures, sach ideation] or neatly identical component that iy illustrated in various figures is represented by a like numeral. For purposes of clarity, not every component may be labeled in every figure. In the figures: FIG. is a schemate representation of one exavaple of a handheld laser system according to aspests of the present disclosure; FIG. 2 is another schematic representation of an example of & handheld laser system according to aspects of the present disclosure; FIGS. JAF illustrate various views of one example of a handheld laser apparatus according to aspects of the present disclosure; and FIG. 4 15 a schematic dagram of a wobbling laser beam emanating from the tip of a handheld spparates in sccordance with aspects of the invention. DETAILED DESCRIFTION As discussed shove, echnical and sconomic advances sre driving demand for handheld lasers with powers of at feast T KW. Handheld laser devices with these power fevels also present & sepavate set of safety issues. For instance, the usar of such a handheld device may mistakenly think laser energy 1s not being emitted since there is no evidence of processing taking place on the workpiece material. This could be caused by any one of a number of different things, sach a3 a damaged laser head, the type of workpiece material being processed, or the method or manner that the user is following during the processing operation. As a consequence, instead of being absorbed in the workpiece material, the laser snergy is reflected off the material. The user may mistakenly believe that the laser is not functioning since the radiation is visible to them, and as a consequence unwittingly subject themselves to prolonged radiation sxposure. The present disclosure discloses a handheld laser device that addresses the above mentioned problem. The handheld laser device is configured with a plasma sensor that is capable of rapadly detecting non-laser wavelength plasma that iS created during a proper material processing operation. When something prevents normal processing from oocurring, such as an inproperdy focused laser beam on the workpiece material, a controller shuts the faser off. This prevents prolonged exposure to laser Hght by 2 user. In addition, according to some embodiments, the devices is ale-cooled which greatly reduces the swe of the system as compared to water or guid refrigerant-based laser cooling systems. As discussed balow, in at least one embodiment the laser module associated with the handheld component can fit on a standard welding cart. This reduced footprint fs advantageous in many processing environments where available workspace is minimal and / or a more portable unit is desirable. Tis to be appreciated that although air-cooled laser systems are described herein, the scope of this disclosure also extends to water-cooled Systems, especially in instances where higher powers {8.g., mulg-kW; are employed. FIG. | llustiates a schematic of one example of a handheld laser system 100 for performing a material processing operation on a workpicee 103. Non-lmiting examples of material processing operations include cutting, welding, brazing, swites modifleation (e.g, material removal such as cleaning), drilling, and in some instances, cladding. The handheld laser system 100 {also referred to herein as “laser system” of simply “system” includes & laser source 115, a plasma sensor 135, and a controller 180. The handheld laser system 100 further comprises 2 housing that is configured ss a handheld apparatus 120 {also refered to herein as a handheld device}, and an optical fiber 130 that couples the laser source 11§ to the handheld apparatus 120. According to at least one embodiment, the handheld laser system 100 further includes a laser module 110 that houses the laser source 118, and in some fnstances, the controller 136. The laser modale 110 may also include an alr-cooling system 140 that cools the laser sowrce 115. In certain embodiments, the handheld laser system 100 alse includes at least one optical fiter 137. The laser sree 115 is configured to generate laser radiation at a wavelength for performing a material processing operation en the workpiece 105 with a taser beam {22 of the generated laser radiation. The laser source 115 may include a Viterbi £YD) laser capable of generating a laser within the near-infrared spectral mange (e.g, a center wavelength ranging from about 1030-1080 nm). Other lasers are also within the scope of this disclosure, including Yb lasers in the 978-1020 nm range, Erbium lasers, and Thulium lasers. As will be appreciated, laser radiation generated and emitted by the laser source 118 is propagated by an optical fiber 130 that extends from the laser sonres 115 tough the handheld apparatus 120, where the laser radiation in the form of beam 122 is emitted through outlet 123. The laser source 119 may comprise one or more laser diodes that generate the laser radiation that is propagated by the optical fiber 130. As sueh, the assembly can be collectively referred fo as & fiber laser. In somes embodiments, the optical fiber 130 has a fength of at least 3 meters (mm), and can be § por even 10 win length. Shorter and longer lengths are also witha the scope of this disclosure. In accordance with various embodiments, differant applications may require differently sized (e.g, core dismmeter) optical fiber 130. For instance, systems that output single mode (SM) laser radiation will have fiber core diameters that are smaller than those that generate multimode (MM) laser radiation. System 100 can be configured to accommodate optical fiber 130 of different sizes depending on the desired output mode. According to at least one embodiment, the laser beam 122 generated by the laser sores 113 has a power of at least | kW, and according to another embodiment the laser beam 122 has a power of at least LS KW. In other embodiments, the laser beam 122 basa power of about 2 EW. In stil other ensbodiments, the laser beam 122 has & power of aboat 3 KW. Lower and higher output powers are also within the scope of this disclosure, For instance, in some applications, the laser source 115 is configured to generate a laser beam 122 having & power of less than 1 XW. In accordance with at least one embodiment, the laser sowree 115 is configured to genernte a laser beam 122 having a power within a range of S00 Wo 3 KW inclusive. To another embodiment, the laser beam 122 has a power within & range of 1 kW to 3 XW inclusive. In another embodiment, the laser source 118§ is configured fo generate a laser beant 122 having s power within a range of 500 Wo 1 KW inclusive. The laser source 118 may be confignwed to emit or otherwise generate single mode {SM} or nudtimode (MM) Hight and may be operated in continuous or pulsed mode, According to some embodiments, the laser source 115 is configared fo generate pulsed laser light having @ high peak power (FPR). This HPP mode can include operating & continuous wave (CW) laser in pulsed mode with ap 10 a two-fold increase in peak power in comparison with CW average power for short duty ayeles (e.g, 0:20%). In some embodiments, HPP mode has & modem duty eycle of about 20% (inclusive). In certain embodiments, for HPP mode the duty eycle is within a range of 0-20% inclusive, in other embodiments the duty cycle is within a range of 0.120% mciusive, in other embodiments the duty cycle is within a range of 1.20% elusive, and in stil other embodiments the duty oyele is within a range of 16-20% inclusive. The HPP mode can also be characterized by having a maxima laser pulse frequency {pulse-repetition frequency} of 1500 Hr (nchusive), although higher laser pulse frequencies are within the scope of this disclosure. According to one non-limiting embodiment, the laser source 11§ is configured to generate Jaser radiation bn 8 OW mods that has an cupat power, and to genome laser radiation in a HPP mode characterized by having a maymman peak power that fe less than twice the cutput power of the CW made, a maximum duty eyele of about 20%, and a maximo pelse-repetition frequency of ahawt 1300 He, Io one example, the peak power in HPP wode is 900 W, In another example, the peak power is 2500 W. In one example, the average COW power is about 1300 W, The HPP mode offers several advantages fo the handheld laser, since this mode of operation allows for the ability to weld thicker parts and for the ability to weld highly reflective metals lke copper. HPP also enhances cutting operations, since {t punches trough thick metals faster and creates a smaller opening, reducing the amount of debris that make their way to the top and consequently reduces the amount of spatter. One non-limiting example of a laser configured as a HPF laser includes the YLS-HFP and YLR-HPP systems available from IPG Photonics (Oxford, Massachusetts). Inaccordance with one embodiment, the laser source 11S andvor laser beam 133 can be classified as a high level class IV (IEC Laser Classification) laser, According to some embodiments, the laser source 118 is configured as a Fabry-Perat MM faser as desortbed fn US. patent no. 9,647,410, which is owned by Applicant and fully incorporated by reference. Such & system may comprise a fiber oscillator that comprises a MM active ber having & monolithic core that is doped with Hight emitters, two MM passive fibers that are spliced to respective opposite ends of the MM active fiber, and MM fiber Bragg gratings (FRGs) that are written into the respective cores of the MM passive bers that fonction to define s resonant cavity therebetween, The laser radiation that is generated emia ats desired wavelength and has a spectra! Hnewidih within range of about £.02 nan fo about 10 nm. In accordance with a farther aspect, a pump on also be incloded that side pumps the active fiber. {rn some embodiments. the laser source may be configured wo generate 3M laser radiation, Yo such instances, the spot size of the laser beast may be smaller {e.g., atleast Sx smaller) than that generated for MM laser mdiation, snd offers the advantage of being useful for copper welding, The housing configured as a handheld apparatas 120 has an outer 123 or exit for the laser beam 122. Throughowt the present description, the term “handheld” Is understood to refer to a laser device that is both small aad Hight enough to be readily held in and opemted by one or Both hands of a wer. Furthenmore, the handheld laser device should be portable, so that it may be easily moved around by the user during laser processing. However, while embodiments of the present invention ave referred to a8 “handheld” and may be weed as sundalone portable devices, the handheld laser device may, in some erbodiments, be connected fo and used in combination with stationary equipment, Tn accordance with certain enabodiments, the handheld apparatus 120 has a weight of fess than § pounds (without fiber), and fn some embodiments, the handheld apparatus 120 has a weight of less than 3 pounds. According to one embodiment, the handheld apparatus 120 has a weight of Joss than { kilogram (kg). In addition, the handheld apparatus 120 has length and width dimensions of fess than 12 inches, e.g, seo the side view perspective of the handheld apparatus 120 in FIG. 3F. In one example, the handheld apparatos 120 bas a width Simension of leas than 10 inches. The entire system 160, according to some embodiments, has a maxima weight of 53 Kg (118 pounds). Tn secordance with af least one embodiment, the handheld apparatus 120 i of one- piece constraction {also referred to as monolithic or integrated construction). The exterior of the handheld apparas 120 is formed of a single integrated materdal, snd not bolted or otherwise fastened together from separate scetions. This type of construction aliows for several advantages. For one thing, one-piese construction provides a more sealed internal environment when compared against devices configured with mudii-part construction that are mechanically fastened together. This feature enbanges protection of the internal components 10 the handheld apparatus 120, e.g, lenses and other optical components, sptical fiber, gas Hines, eto, and allows for lgher ouput powers by the device, According to some ernbodirpents, the handheld apparatus 128 is configured witha modular attachment system for a noazle. This allows for the handheld apparatus 120 0 Function as a single “base” module, thus allowing substitution and flexibility in providing different attachrnent nozeles 1 the handheld apparatus 120 for various apphoations {s.4., cleaning, welding, drilling, cladding). This is implemented at least in pant by the handheld apparatus 120 being configured to internally integrate several auxiliary and / or other components, such as shielding gas, a protective window{s}, and safety features such as safety mtariock conductors that are Integrated within the interior of the handheld apparates 128, The handheld apparatus 128 is also configured to have a clear tine of sight {for the operator} fo the processing area {Le., where the material processing operation is scouring on the surface of the workpiece) of the workpiece 105. This is evidenced by the views shown in FIGS, 3C and 3D, where the angled portion 113 {see alse FIG. 3F) of the handheld apparatus 120 is configured to not impede the ne of sight along the dimension of the device that includes the nozzle 12. No other portion or attachment impedes this Hine of sight either, This allows the user to have a direct Hae of sight down fo the nozzle Hp and allows for better visibility for the user of the processing area during material processing operations. During a proper material processing operation, heat from the laser beam 122 of the laser source 118 causes the workpiece material 103 to generate a plasma 107. This plasma 107 radiates radiation at a different wavelength or wavelengths than that of the laser beam 122. For instance, light from the laser source 115 may ent at & wavelength in the IR range, whereas plasma generated from the processing beam may have wavelengths in the ultraviolet and visible regions of the electromagnetic spectrum. The plasma sensor 139 is configured detect plasma smitied fom the workpiece material 105 during a material processing operation. The plasma sensor 138 can be a photodetector, such as a photodinde. The photodetector converts the received plasma light mio electrical energy fe... current signal} corresponding to optical intensity data. This optical intensity data is analyzed by the contrefler 150, as discussed in farther deta] below, As will be appreciated, sucrent generated by the photodetector can then be converted to optical intensity data by the controller 150. According to at feast one non-fimiting sxample, the photodeteetor may have a bandwidth of up to or greater thay approximately | MHz, However, itis to be appreciated that the bandwidth of the photodetector will depend on a particudar application, as weil as other components, including the leagth of the optical fiber 130. Unlike some conventional laser systems, the configuration deseribed herein doses not have to fnchude an additional spectrometer, which makes the system cheaper and less complivated to operate. As shown in the example shown in FIGS. | and 2, af least one optical filter 137 ws configured to black or otherwise absorb light at the wavelength of the emitted laser light {fro the laser source 115) from reaching the plasma senser 135. One or move optical filters 137 can be positioned upstream fom the plasma sensor 138 and filter out wavelengths of light associated with the laser source 118, such as jaser source Hight that reflects off the workpiece material 105. For instance, the at least one optical filter 137 may be configured to block about 99.9% of the laser souros 115 Nght, such as 1070 wm (IR) Hght emined from a Yb laser source 118. The optical flier 137 may therefore be configured as an IR suppression filter. The optical filter 137 is designed to allow wavelengths of light associated with the plasma to reach and be detected by the plasma sensor 135. For instance, infrared hight wavelengths may be blocked by the optical filter 137, but visible and near-UV Hght ave passed on through {o.g., 300 — 750 nm). According to one embodiment, the optical Siler is constructed from KG3 glass (manufactured by Schott Optical Company}. In some instances, the optical filter(s) 137 is integrated with the plasma sensor 135, One non-limiting example of such & device is the Series § OSD photodetector avaiable from OST Optoelectronics, ine. of Hawthorne, California, Although the examples discussed herein inclade an optical filter for blocking wavelenghis) of light associated with the processing laser, if 18 10 be appreciated that in cottain instances the plasma sensor may be configured to be insensitive fo this wavelengthis). The controller 1530 is coupled fo the plasioa sensor 138, as Indicated in FIGS, Land 2 such that i is capable of receiving optical intensity data from the plasma sensor 138. The controfler 150 is also fn commmunication with the laser sowoe 118, Including Hs power source such that the controler can control power {Le., tom on and off power) © the laser souree 115. As will be appreciated, the plasma sensor 138 may be used in cornbination with a logarithic amplifier. The controller 130 is configured to compare an optical intensity value obtained by the plasma sensor 135 fo a threshold value 81 a time when @ predetermined time period has elapsed after a material processing operation has commenced. Once the laser sowce 115 has been activated by the user and a raaterial processing operation has begun, the clock stars for the predetenined time period. The predetermined time period can be pre-programmed info ar otherwise determined by the controller. During this predetermined time period, optical intensity dat is collected by the plasma detector 135 and sent to the controller 150. The controller 150 fs pre-programmed or otherwise configured to determine & threshold value for the optical intensity data associated with the plasma 107. This threshold value signifies a “normal” or otherwise aceepiable optical intensity value of plasma generated during the material processing operation. The optical intensity may therefore be associated with a brightness or lominance of the plasma 107. The predetemmined time period can be associated with a typleal or otherwise acceptable amount of time for plasma 107 0 be generated by the faser beam 122 during novmal operation. This will depend onany one of a number of different factors, inchuding the geometry and material of the workpiece, the power of the laser, as well as the type and configuration of the laser. According © some embodiments, the threshold value can also be dependent on the type of material befng used ss the workpiece and / or the type of application beng performed. For instance, alominum and steel may have different Greshold values, and a cleaning operation may require a differant threshold thas welding andor drilling operations. In sccordance with Cenatn embodiments the predetermined time period is less than one second, and in some instances can he in a range of 10 microseconds {us) to 100 milliseconds {ms}. According fo one embodiment, the predetenvined Hime period s at least 10 ug, and according to another embodiment, i at least 100 ge. In still other embodiments, the predetermined time perfod Is at least one second. The time of analysis by the controller 150 can be {af a minimum) as soon as the predetermined time period has elapsed. In some instances, the plasma sensor 133 may collect a series of measured optical intensity values and the controller 150 then uses an average or maximum for performing the comparison to the treshold value. In other instances, the controller 150 can infegrate measured optical intensity data and use this information for performing the Companson. In accordance with some embodiments, the predetermined time period can aldo be a function of laser power, For instance, some applications may require {or it may be desired by the user) that the laser come up to full power prior to performing a material process operation. In some instances, this can extend the predetenmuined time perlod. For instance, the predetermined time period may be ap fo one second. In some instances, the time petiod for the laser to come up to full power may be considerad or otherwise taken iow accoent separately from the predetermined time period associated with plasma generation. The controlier 136 can be configured to scoount for both, The controfler 150 i also configured to produce a control cormand based on the comparison between the optical intensity value of the plasma and the threshold valve, For example, the controler 150 will um off power to the laser source 115 when the optical intensity value is Tower than the threshold value, This could signify that « Jaser beam 132 8s indeed being generated, but it is not being absorbed by the workpiece material 103. This presents a potentiaily dangerous condition for the user. As discussed above, other problems can also cause plasma 1 not be created. The controller 184 will maintain power to the laser source 115 when the optical intensity value is af or greater than the tweshold value. This would signify “nonmal” material processing conditions. Put another way, a treshold ts set of expected light energy from the material processing operation, and the laser source 115 is shat Off by the controfler 130 if this expected Hght energy is not sensed within a specified time. The threshold value ean depend on the application and other factors, including laser power, beam configaration, sad workpisee materials and material geometries. In some instances, the threshold value will be a percentage (9%) of an expested value, such as 10-50% of an expecied value, e.g, an expected value at a particular laser power. Its to be appreciated that a noise filter may also be incladed or otherwise implemented by the controller 130 to filter out noise that impedes the ability for the controller 130 to process the optical intensity data. The threshold value can also be set to take into account or otherwise accommadate appheations where the laser fs modulated (Le. faser power varies, such as pabsed mode}. For mstanee, the laser power can be modulated when the laser fs functioning with wobble capability (described in more detail below} The controller 150 may be any computing device {or devices) that includes at least OnE PrOCESSaT, a memory, inpuloutm components as will be readily appreciated by those of skill in the art, and is capable of receiving, wansforming, andéor analyzing data from the plasma sensor 138, The controller 150 may include hardware and / or software capable of wansforming anddor analyzing information from the plasma sensor 135 and other components of the device or system, The handheld laser system 100 also includes an air-coolng system 140 that Is coupled to the laser source 113 for purposes of dissipating heat. As mentioned above, alr-cooling the device greatly reduces the size of the system ss compared to water or Hud refrigerant-based laser cooling systems. According to at least one embodiment, system 100 ean also nclode a Taser modide 110 that houses the aircooling system 140, laser source 115, and conweller 180. As indicated in FIG. 1, the laser modide 110 can be configured to be mounted to a movable cart 160. in one example, the movable cart 160 has the dimensions of & standard welding cat, e.g, 36 inches or less in length and height, and 24 inches or less in width, although itis to be appreciated that some welding carts may have dimensions that slightly differ or otherwise differ from those listed herein. According to one embodiment, the lasar module 114 itself can be sized to be loss than 26 inches in length, Tess than 12.3 inches fn width, and fess than or equal to 21 inches in height. Referring vow to FIGS. 3A-3F, there ave various views of one non-limiting example of & handheld apparatus 120 which has & size and shape for user portability for the purpose of performing laser material processing operations such as welding or cutting, In this example embodiment, the handheld laser devices resembles x guns shape. According to some embodiments, syste 100 can also inolude 8 wire feeder module {not shown in figures) that can be configured ss a sepamte module, or in some stances be integrated with the faser module 110. The contrefler 150 can also be configured to control this wire feader mode. In recordanee with another aspect, the handheld apparatus 126 is configured to be gas~cooled. For mstance, the handheld apparatus 120 may have one or more infets for a gas such as a shielding gas {or afr fn certain applications) that is directed through one or more conduits within the interior of the handheld apparatus 120. This means that no cooling water {or other liquid cooling Hud) nuns trough the handheld apparatus 120. In one embodiment, shield gas is directed into two {or more) conduits or channels located at an inlet or otherwise focated internally fo the handheld apparates (shown generally at 124 fa FIG. 34), and the conduits traverse the inferior and exit at a gas outlet located within the vicinity of the outlet 123 for the laser beara. Yo some instances, (he gas is shielding gas that can exit trough the nozzle {e.g, nozzle 112 of FIGR. 3A-3C) As the gas traverses the interior of the handheld apparatus 120 # cools various heated components, such as optical components (e.g, lenses, nivrors) anddor electronic components such as motors. Feeding or otherwise directing & gas such as shielding gas through the housing / handheld apparatus 120 not only functions to cool heated internal components, but also adds to the nozzle modularity concept discussed above since no external tubing or wiring is required. According to the example shown in FIGS. 3A.3F and in accordance with at least one embodiment, the plasma sensor 135 may be positioned within an fateror of the handheld apparatus 120. This is most clearly shown in FIG. 38, which includes 8 cutaway view of a portion of the interior of the handheld apparates 120. In altemative embodiments, the plasma sensor 135 may be positioned on an exterior of the handheld appamtus 120. According {0 at least one embodiment, the handheld apparatus 120 includes a wigges, button, of switch 123 {and may be referred to herein as simply a trigger) that is coupled to at least one of the controller 130 and a source of shield gas 145 that controls activation of the shield gas. For instance, as shown fn FIGS, 3A and IB, shield gas 1435 canbe guided through # tube within a flexible conduit 117 that also houses the optical fiber 130 and then through a nozzle 112 and removable processing tp 126 where # can be dispensed onto the workpiece material As will be appreciated, the shield gas prevents the workpiece matedal from overheating during processing and / or to prevent debris from contaminating componants of the handheld apparatus 126. The handbeld apparates 1230 also includes & rigger, button, or switch 121 {alse referred fo herein as simply a tigger) that is coupled fo at least one of the convoller 130 and the laser source 115 that controls activation of the laser source 115. As shown fn FIGS. 34 and 3B, electrical cabling 119 positioned within the flexible conduit 117 can include wiring such that the trigger 121 fs in communication with a1 least one of the controller 136 or the taser source 115 for controlling activation of the laser source 115. To accordance with at least one embodiment, trigger 125 is a {vet trigger and trigger 121 is a svoond trigger that are configured in a two-stage arrangement such that the second rigger 121 will not activate the laser source 11§ unless the first trigger 129 is already activated. For example, during operation, a user will fivst press trigger 125, to activate the shield gas. Then the user can press trigger 121. Second trigger 121 will only activate the laser source 118 if fest trigger 123 is depressed. This provents the workpiece material 103 and / or handheld apparatus 120 from being damaged. One or both of the fivet trigger 128 and second trigger 121 can also be configured 0 have independent functionality. For example, the second trigger 121 can be released without releasing the first trigger 125 fo shut off the laser, and then pressed agam fo fam on the laser if the first trigger 125 is still pressed. Furthermore, the frst trigger 125 can be released regardless of the state of the second trigger 121 {o shut off the laser. As can be appreciated, trigger buttons can be part of an overall safety meerlock system that includes several interlock loops. For instance, frst trigger 135 can engage an interlock {oop that closes when the first trigger 125 is pressed. The second trigger 127 oan be & start button and an additional interlock loop that closes when pressed. Furthermore, pressing the first tigger 128 will turn on the shield gas if one or more other interlock loops are active, e.g, 8 key switch fnterfock loop that engages with the controller {processor) and laser, an emergency-siop loop, & fiber interlock loop, and an extemal interlock loop. When the first rigger is released, shield gas can be kept on for a predetermined duration of dime (e.g, set by a user). The second wigger 121 can act 83 a start button for the laser. If the switch is open for more than a predetermined amount of thoe {a.g,, 300 me) and then trigger 121 is pressed, the laser will fire provided that the safety condivons have been satisfied and the shield gas has Seen on for a predetermined duration of thine {and in some stances, as previously mantioned, the laser has reached & desirad output power level) As previously mentioned, the handheld laser can include several safety Interlock loops that prevent operation of the laser if a fatlwre is detected. Non-Hmiting examples of such interlock loops include a keyswiteh / s-stop interlock loop, an external interlock loop (e.g, an interfock loop that engages with the laser system and a user’s extemal safety mechanism), a fiber interlock Toop, a head novele and safety clip buerloek loop, 8 two-level trigger interlock loop, safely latch interlock loop, and current source interlock loop. Other non-limiting examples of safety interlock loops that may be included in the device include those associated with temperature {eo g., device and / or aly lemperatire sensors), gas pressore, and / or additonal phatodetactors {e.g., for back reflection, dirty window, fiber fuse, sic) To assist the user, the handheld apparates 120 may also be configured with one or more status lights 127 {e.g see FIG. 3D) that inform the user of the operational status of the device. When the status Hghts 127 are not Bt, this indicates a default state (Le, no shield gas or laser Hight energy is being emitted from the handheld device). When the user depresses trigger 125, this activates the shield gas, which in turn activates status Hght 127a {for inthe alternative, 1275) This signifies to the user that shield gas is being emitied. Ones the user depresses trigger 121 {while still pressing trigger 128), this activates the laser source 118, which in turn activates status Nght 1270 {or in the alternative 1272). When both status Habis 1272 and 1275 are By, this signifies to the user that the shield gas and laser Ugh are being emitted from the handheld device 120. in some instances, this can signify 0 the controller 184 the start of the predetermined time period discussed above. The handheld apparatus 120 may also be configured with one or more optical components, such as a replaceable window (indicated as 128 in FIG. 3, but located internally) used to protect the internal components of the handheld apparatus 120, as well as a replaceable focus lens (Indicated as 129 in FIG. 3C, but located internally), which Is used fo focus the laser beam 122 onto the workpiece sweface. Other lenses (e.g, 3 collimating lens) or optical components, {o.g., bean splitters, mirrors) can also be implemented within the handheld device 120. In some instances, the handheld apparatus 120 reay include a coupler or other waveguiding component for connecting fo optical fiber 130. The handheld apparatus 126 can also nehude other components, such as a removable or sliding boot or collar 141 {e.g soo FIGS, 1B and 30) that covers connections 10 components that are within a flexible conduit 117 that extends between the handheld apparates 120 and the laser module 110, such as the optical fiber 139, shield gas 148, and / or electrical wiring 119. The handheld lager system 100 may also include or otherwise implement one or move additional safety features. For example, in one exabodiment, the handheld apparatus 120 configured with a position sensor to ensure the nozzle or tp is touching a surface of the workpiece, For instance, a safety tnterfook implemented via the controller 150 can be incorporated with the removable processing tp 126 and a power sree for the laser sources 115. During use, the controler 130 will only activate power to the laser source 115 ifthe safety interlock is engaged, Le., the nozele or Up of the handheld appasates 120 is engaged with the workpiece. Tn one example, this can be implemented by electrically connecting the workpiece and the head nozzle by clipping the workplecs to the laser systems, .3., 8 terininal ona pane! of the system. 17 In accordance with at least one smbodiment, the handbeld apparatus 120 is alse configured with beam wobbling capability. For instance, at least one movable mirror may be positioned within the housing 120 that is configured 10 wobble the laser beam 122. The wobble motion oseillates the laser beam 122 back and forth at a desired frequency {e.g wp to 300 Hz inclusive, minimum of 30 He, but itis 1 be appreciated that other values are within the scope of this disclosure). The movable mirror reflects and moves the laser beam, Le, wobbles, the laser beam in one axis. In some embodiments, the at least one moveable mirror is configured to wobble the laser beam 122 withun a fleld of view defined by a scan angle within a range of 0.17 fo 3° inelasive, According to other embodiments, the scan angle is within a range of 0.1% to 7° inclusive, and wm other ernbodiments, the scan angle fs within a range of 0.17 to 12° melusive, Larger soon angle ranges are also witha the scope of this disclosure. The different ranges of scan angles may be associated with different types of applications. For example, in welding spplications, the desired scan angle may be smaller thay for cleaning operations. The wobbling capability is possible because the movable mirror is prvotable about one axis and is movable by & galvanometer motor, which fs capable of reversing direction quickly. For instance, the controller 150 controls the movable mirror such that the mirror pivess the bean 122 within a scan angle alpha {o), as shown in FIG. 4, thereby allowing the beam to wobble. Depending on the foes! length (non-limiting examples of which can be 80 nun, 100 sam, 130 man), & 3° sean angle represents wp to about 50 mrad of wobble. ln some instances, the wobble length (wobble amplitude} has a minimum value of about 0.5 pun and 8 maxon vahie of about § om, and In some stances has a rvaximum value of about 4 mm. As previously mentioned, larger scan angles are also within the scope of this disclosure, including 80 nad of wobble, or 4.5%, and even larger wobble amplitudes are also feasible, especially for cleaning operations where the suplitude can be greater than § mm, such as 0415 mo In accordance with at least one aspect, a focus lens is positioned downstream from the mirror. The wobble motion can be one-dimensional, or woe dimensional if the device is equipped with two movable mirrors. Aspenis of the wobbling capability ave desoribed in US. Patent Apphoation No. 15 / 187.238, which is owned by Applicant and fs fully incorporated herein by reference. According fo some embodiments, the handheld apparatus 120 may also include a fixed mirror. Wesides material processing operations such as welding, as mentioned above the systems and methods described herein oan also be applied © surface modification applications, such as material removal {laser ablation). In such instances, the device may be equipped with & wider nozale than that used for welding, sud the scan angle of the wobble may also increase, To addition, the laser source may be operated in pulsed mode or other modes, including the HPP mode of opemtion, The asprets disclosed herein fn accordance with the present {nvention, are not hinted in their application fo the details of construction and the arvangement of components set forth wm the following description or dlustrated m the accompanying drawings. These aspects are expable of assuming other embodiments and of being practiced or of being camied out in various ways. Examples of specific inplementations are provided herein for iHusteative purposes only and are not intended to be funiting. In particudar, acts, components, clements, and features discussed in connection with any one or more embodiments are not intended to be exchided from a similar rols in any other embodiments. Also, the phraseology and terminology used hereln fs for the purpose of desorption and should not be regarded as Hmiting, Any references to examples, embodiments, components, elements or acts of the systerns and methods herein referred to in the singdar may also embrace embodiments including a plurality, and any references in plural any embodiment, component, slement or act herein may alse enabrace embodiments including only a singularity. References in the singular or plural form ave not intended to Umit the presently disclosed systems or methods, thelr components, acts, or elements. The use herein of “Including,” “comprising,” “having,” “containing,” “lvelving,” and variations thereat is meant to sncompass the items listed thereafter and equivalents thereof as well as additional items, References to “or” may be constroed as inclusive so that any terms deseribed using “or” may indicate any of a single, more than one, and all of the deseribed terms. In addition, in the event of inconsistent usages of terms between this document and documents meorporated herein by reference, the term usage in the meorporated reference is supplementary to that of this document; for irreconcilable inconsistencies, the term usages in thug document controls, Having thus described several aspects of at least one example, it 1s 10 be appreciated that various alicrations, modifications, and improvements will readily oconr to those skilled in the art. For instance, examples disclosed herein may also be used in other contexts. Sueh alterations, modifications, and improvements are intended to be part of this disslosure, and are intended to be within the scope of the examples discussed herein, Accordingly, the foregoing deseription and drawings are by way of example only. What is clammed is

Claims

CLANS 1 A handheld laser system, comprising! a laser source contigured to generate laser radiation at a wavelength for performing a material processing operation on a workpiece material with & laser beam of the generated faser radiation; a plasma sensor configured to detect plasma emitted from the workpiece material during a material processing operation; and a controller coupled to the plasma sensor and configured tor compare an optical intensity value shtained by the plasma sensor 0 a threshold value at a time when a predetennimed time period has slapsed after the material processing operation has commenced; and produce a control command hased on the comparison. 2 The handheld laser system of claim 1, wherein the control command tamms off power to the laser source when the optical intensity value is Jower than the threshold value, and maintains power to the laser source when the optical intensity value is at or greater than the threshold value, 3 The handheld laser system of claim 2, wherein the predetermined thoe period is at least 100 microseconds {us) 4 The handheld laser system of claim 1, further comprising at least one optical filter configured to block light at the wavelength of the emitted laser Hight from reaching the plasma sensor. $s. The handheld laser system of claim §, further comprising an ai-cooling system coupled to the laser source for dissipating heat.

8. The handheld laser system of claim §, further comprising a laser module that houses the lager source, the alr-cooling system, and the controller, z The handheld laser system of claim 6, wherein the laser module is configured to be 8) mounted to a movable cart, 8 The handheld laser system of claim 1, farther comprising a housing configured as a handheld apparatus having an outlet for the laser beam. S. The handheld laser system of claim 8, wherein the handheld apparatus is of one-piece construcHon, 10. The handheld laser system of claim 8, wherein the handheld apparatus is configured with a modular attachment system for a nozzle, 11. The handheld laser system of claim §, wherein the handheld apparatus is configured 10 he gas-cooled.

12. The handheld laser system of claim 8, wherein the handheld apparaws i configured to weigh less than about | kilograra (kgs.

13. The handheld laser system of claim 8, wherein the plasms sensor is positioned within an interior of the handheld apparatus.

14. The handheld Inser systern of clade 8, father comprising an optical fiber coupling the handheld apparatus to the laser sauce.

18. The handheld laser system of claim §, wherein the handheld apparatus comprises a teigger coupled © at feast one of the controfler and a source of shield gas that controls activation of the shield gas.

16. The handheld lager system of clmint 15, wherein the trigger is a first trigger and the handheld apparatus further comprises a second trigger couplad to at least one of the controller and the lager source that controls activation of the laser source.

17. The handheld laser system of claim 16, wherein the first and second trigger are configured in a two-stage arrangersent such that the second trigger will not activate the laser source unless the first wigger is activated.

18. The handheld laser system of claim 8, further comprising at least one movable mirror positioned within the housing, the at least one movable mirror configured to wobble the laser Beam.

18. The handbeld laser system of alain 1, wherein the laser beam has a power of at feast 1 XW.

20. The handheld laser system of elaum 19, wherein the laser beam has a power of about 185 kW.

21. The handheld laser systern of claim 1, wherein the laser beam has a power withina range of 360 W to 3 KW inclusive. 22 The handheld laser system of clafm 1, wherein the laser source is configured fo: generate laser radiation in a contimious wave (CW) mode that has an ouput power; and generate laser radiation in a high peak power (HPP) mode characterized by having a maxinaan peak power that fs less than twice the output power of the CW mode, a maxinum duty oyele of shout 209%, and a maximum pulse-repetition frequency of about 13606 He, 33. The handheld taser system of claim 1, wherein the wavelength i fnfrared (IR) Hght and the at least one optical filter is configured as an IR suppression filter, 24. A method, comprising: directing a laser beam from a laser source onto a workpiece material; activating & plasms sensor configured to detect plasma emitted from the workpiece material during a material processing operation; comparing an optical intensity value obtained by the plasma sensor to a threshold valae at & time when a predetermimed time period has elapsed after the material processing operation has commenced; and woducing a control command based on the comparison.

38. The method of claim 24, wherein the control command powers off the laser scuree when the optical intensity value is lower than the threshold value and maintains power © the laser source when the optical intensity value is at or greater than the threshold value.

26. The method of claim 24, firther comprising positioning at least one optical fiter configured to block light at a wavelength of the laser source such that Hight at the wavelength of the laser source doas not reach the plasma sensor.

27. The method of claim 24, further comprising providing a bousing configured as & handheld apparatus having an outlet for the laser beam.

8. The method of claim 24, further comprising providing an optical fiber that couples the handheld apparatus to the laser sources.

29. The method of claire 24, fiwther comprising wobbling the laser beam.

38. A handheld laser system, comprising: a laser source configured fo generals laser radiation at a wavelength for performing a material processing operation on a workplaces material with a laser beam of the generated {aser radiation; and a housing configured as & handheld apparatus having an outlet for the laser beam, the handheld apparatus configured to be gas-cooled 31. The handheld laser system of claim 36, further comprising an optical fiber coupling the handheld apparatus fo the laser source.

32. The handheld fasor systom of claim 3¢, wherein the handheld apparatos {s of one piece construction.

33. The handheld laser system of olaim 39, wherein the handheld apparatus is configared with & modidar attachment system for 8 noaele. 34, The handheld laser system of claim 30, farther comprising an alr-coolng system coupled to the laser source for dissipating heat, 33. The handheld faser system of clabm 34, further comprising a laser module that houses the laser source, the afr-cooling system, and the controller. 36 The handheld laser system of claim 33, wherein the laser module is configured to be mounted (oa movable cant, 37. The handheld laser system of elaim 30, wherein the laser beam bas a power of at feast 1 kW.

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